A maniac is on the loose, viciously slashing his victims and leaving them to die on desolate streets. The city is driven to panic by the seemingly random violence, perpetrated by a criminal known only as Splitface. Time is running out for detective Dick Tracy when the mayor is targeted as the killer's next mark. As he begins to piece the scraps of evidence into a solid case, Tracy's girlfriend is taken prisoner by Splitface at his riverboat hideout. With his motive exposed and nowhere to hide, the horribly scarred villain is confronted by the detective in a violent showdown.